Mid—Infrared Optical Parametric Oscillator Based on All—Solid—State—Pumped Periodically Poled LiNbO

We report the tunable mid-infrared generation with a periodically poled LinbO3(PPLN).Using an all-solid-state pumped Nd:YVO4 laser as the pump source and a PPLN nonlinear crystal with grating periods of 28.2-30.8μm,we have achieved wavelength conversion in the 2.90-4.05μm spectral range by period tuning.The use of confocal cavity design has brought a compact,all-solid-state configuration with an average output powers of idler up to -200mW.The maximum power of 277mW was obtained at the wavelength of 3.35um.     

Three Stilbene Tetramers from the Roots of Caragana sinica

Three stilbene tetramers, carasinols A-C (1-3), along with three known substances, leachianol C, cararosinol A and stenophyllol B, were isolated from the roots of Caragana sinica. Their structures were elucidated by spectroscopy. It was found that compounds isolated except for stenophyllol B stimulated the proliferation of cultured osteoblasts.     

氘代聚合物膜靶制备技术与性能研究

 氘代聚合物膜是快点火基础物理实验的一种重要靶型。通过氘代苯乙烯单体的本体自由基聚合反应制备氘代聚苯乙烯，并利用流延法和浇铸法制备出厚度从几十nm到数百μm的膜靶。溶剂挥发过程中的随机扰动对膜厚均匀性造成影响，采用清洁的基片和在涂沫基片或模具外加防护罩可以降低这种影响。采用PVA作脱膜剂有利于获得较薄的聚合物薄膜。DSC分析表明薄膜的玻璃化转变温度与热处理过程有关，缓慢退火有利于提高Ｔ-g和储能模量。     

分光光度法测定环境水样中的汞

研究了氯磺酚偶氮硫代若丹宁 ( HSCT)与汞的显色反应 ,在醋酸介质中 ,HSCT与汞反应生成 2∶ 1稳定络合物 ,λmax=5 4 5 nm,ε=5 .66× 10 4 L· mol-1· cm-1。汞含量在 0— 2 .5μg/ m L范围内符合比耳定律 ,本方法可用于水样中痕量汞含量的测定     

A Complexity View of Acid Deposition

We show that acid deposition is analogous to complex systems composed of a series of interconnected components. Frequency-size distributions of weekly hydrogen deposition (WHD) of precipitation are consistent with double power-law in two different regimes separated by a crossover WHD. The distribution of variations in acid deposition over a week interval is remarkably symmetrical, with long tail extending over eight orders of magnitude. The acid deposition fluctuations exhibit fractal Brown motion with two different temporal scaling regimes and long-range correlation exists in the series. The power-laws in the acid deposition dynamics are considered to be indicators of self-organization of atmosphere under environmental pollution stress.     

二代树状碳硅烷液晶研究Ⅰ.端基含36个丁氧基偶氮苯介晶基元

用发散法合成周边含36个丁氧基偶氮苯介晶基元(M5)端基新的二代树状碳硅烷液晶(D2),并用元素分析,氢谱,激光质谱,红外,紫外,偏光显微镜,DSC和WAXD法表征.D2为向列相,与M5相同,二代树状物相态由介晶基元相态决定.D2液晶态相行为是K85N107I103N69K,其熔点比M5降低27～41℃,清亮点比M5降低17～18℃,液晶态温区比M5加宽10～23℃.二代碳硅烷(D2)与一代碳硅烷(D1)相比熔点增加2～3℃,清亮点降低26～29℃,液晶态温区减少29～31℃.在二代树状物中观察到S=+3/2的高强向错.     

镁离子内扩散铌酸锂研究(Ⅱ)—— X射线衍射和扫描电子显微镜表征

对不同扩散条件的铌酸锂单晶基片进行了X射线衍射分析(XRD)和扫描电子显微镜观察(SEM)。结果表明,在扩散表面富镁层出现一新相结构,可能是由Li-Mg-Nb-O组成的三元系相结构,这一新相被认为是镁离子内扩散的真正扩散源。并对晶格发生畸变、镁离子内扩散机理以及镁的扩散层折射率变化机理进行了分析和讨论。 关键词：     

硫烷化学

硫烷是一类具有三中心四电子过价键的化合物，它即可以作为特殊的反应试剂，又是有机反应的重要中间体。本文对其结构，合成，性质及其应用作一简单综述。